1. Field of the Invention
The present invention relates to a communication device for a vehicle for wireless transmission of vehicle-related data to another vehicle or an infrastructure as part of wireless vehicle-to-environment communication.
2. Related Art
Vehicle-to-environment communication (C2X or V2X communication) refers to wireless communication that can take place as vehicle-to-infrastructure communication (C2I) or vehicle-to-vehicle communication (C2C). This communication involves the transmission of various information as signals on different radio channels according to the content of this information. Wireless communication based on an intelligent transport system (ITS) communication standard, as specified in IEEE 802.11p, is used in particular for this purpose in Europe and the USA. Other standards exist, however, some of which are also used. Communication in accordance with IEEE 802.11p takes place in Europe, for example, in a frequency band from 5.875 to 5.905 GHz, with implementation of a control channel (CCH) and at least two service channels (SCH). The control channel is used for the broadcast communication in which a piece of information is meant to be transmitted to a plurality or all of the users in the communication network. This channel is reserved for brief, safety-critical information having only short latency times and for communication management. The service channels are used for transmitting additional, non-safety-critical data, for instance application-specific information, road geometry, etc.
One of the basic principles of C2X communication is that information is generated and relayed by numerous users in a network, in particular numerous vehicles. Many applications implemented using C2X communication use this network or involve generating and relaying as much information as possible concerning the safety of continued movement, e.g., relating to traffic jams or other obstacles or relating to the statuses of the vehicles themselves.
Document WO 2009/074655 A1 discloses a communication device for a vehicle that can be used to perform such a communication. Examples of the use of C2X communication are an intersection assistant, drive authorization applications, locating a parked vehicle, pedestrian detection, accident assistant, parking assistant or the like.
It has been assumed until now that vehicles can only be equipped with such a communication device in the factory. If such a communication device is used, especially if it has been designed in accordance with IEEE 802.11p, there could be problems regarding acceptance when such communication devices, or a communication system using such communication devices, are first launched, because the rate at which vehicles are equipped will initially be low. In the launch phase of a C2X communication system it is highly likely that an owner of a vehicle containing a sophisticated C2X communication device only enjoys a few advantages from this device because the number of vehicles equipped with such a communication device is still too low. This problem could hinder or at least delay the launch of the extremely useful system per se.